Telescoping members such as tow bars are known in the prior art which are arranged to be folded when not in use for storage purposes. Also, known tow bars include telescopically adjustable members which are secured by locking. However, in the prior art structures, there is considerable difficulty in releasing the locking mechanism for the tow bar members especially when the towed and towing vehicles are stopped at a position where there is a tension force on the tow bar members. In such a situation it is necessary to dismount the towing vehicle to manually force disengagement of the locking mechanism by utilizing a hammer or the like.